SOUTHERN OCEAN CURRENTS
Map from: http://www.polar.org/antsun/oldissues2002-2003/Sun121502/current.html
FROM: The Antarctic Coastal Current
Joanna Gyory, John Cangialosi, Ieng Jo, Arthur J. Mariano, Edward H. Ryan
http://oceancurrents.rsmas.miami.edu/southern/antarctic-coastal.html
The Antarctic Coastal Current, also known as the East Wind Drift Current, is the
southernmost current in the world. This current is the counter-current of the largest ocean
current in the world, Antarctic Circumpolar Current. On the average, it flows westward
and parallel to the Antarctic coastline. Although it is circumpolar, the Antarctic Peninsula
partially impedes its flow (Tchernia, 1981; Grelowski and Pastuszak, 1984). The current
is an important component of the very active air-sea exchange in this area that leads to
deep convection and production of deep ocean water masses. The Antarctic Bottom
Water and Antarctic Intermediate Water obtain their fundamental characteristics
(Tchernia, 1981) in this region.
The Antarctic coastal zone shares some similarities with other coastal zones, but is
dominated by relatively unusual aspects. First of all, location of the "coast" changes
dramatically on an annual basis, because sea-ice extends hundreds of kilometers from the
land in winter, before melting back to close to the shore in summer. Ice advances most
rapidly in May and June, reaches maximum coverage in September, retreats most rapidly
in November and December, and it reaches a minimum in February (Deacon, 1984). This
annual expansion of sea-ice covers 22 million km2 in winter but only 8 million km2 in
summer, and is such a dominat aspect of the waters sorrounding Antarctic that any
assesment of processes in the coastal zone must include the entire region anually covered
in sea ice. Secondly, the coastal shelf sorrounding Antarctica is relatively narrow and
deep. This aspect, the dispersive nature of the Southern Ocean sea-ice circulation, and the
lack of riverine inputs represent key differences from the conditions which prevail in the
Arctic (Tchernia, 1980).
FROM:The Antarctic Circumpolar Current
Ryan Smith, Melicie Desflots, Sean White, Arthur J. Mariano, Edward H. Ryan
http://oceancurrents.rsmas.miami.edu/southern/antarctic-cp.html
The Antarctic Circumpolar Current (ACC) is the most important current in the Southern
Ocean, and the only current that flows completely around the globe. The ACC, as it
encircles the Antarctic continent, flows eastward through the southern portions of the
Atlantic, Indian, and Pacific Oceans. Edmond Halley, the British astronomer, discovered
the ACC while surveying the region during the 1699-1700 HMS Paramore expedition.
Later, the famous mariners James Cook in 1772-1775, Thaddeus Bellingshausen
(Estonia) in 1819-1821, and James Clark Ross in 1839-1843 described the Atlantic
Circumpolar Current in their journals. Cook was the first person to use the term, Southern
Ocean, to describe this area. Other notable expeditions were made by Sir Drake, who
reached the tip of South America in 1578, Abel Tasman, who sailed south from Australia
into the Southern Ocean in 1642, James Weddell in 1823, and by the HMS Challenger in
1873-74 (Deacon, 1984).
The ACC is arguably the "mightiest current in the oceans" (Pickard and Emery, 1990).
Despite its relatively slow eastward flow of less than 20 cm s-1 in regions between the
fronts, the ACC transports more water than any other current (Klinck and Nowlin, 2001).
The ACC extends from the sea surface to depths of 2000-4000 m and can be as wide as
2000 km. This tremendous cross-sectional area allows for the current's large volume
transport. The Antarctic Circumpolar Current's eastward flow is driven by strong
westerly winds. The average wind speed between 40°S and 60°S is 15 to 24 knots with
strongest winds typically bewteen 45°S and 55°S. Historically, the ACC has been
referred to as the 'West Wind Drift' because the prevailing westerly wind and current are
both eastward.